The interval between introduction and availability for the Surface Pro 3 was both in line with and longer than Microsoft's practice for the laptop replacement's previous editions.

Of the five models Microsoft introduced Tuesday, two -- the Intel Core i5-powered configurations with 128GB or 256GB of storage space -- will ship next month in the U.S. and Canada. Those models, which list for $999 and $1,299, will ship June 20 and go on sale in the company's own retail stores as well as others. Microsoft will deliver the $130 Surface Pro Type Cover, a new keyboard sized for the larger Surface Pro 3, on the same day.

The other three models, including the entry-level $799 Core i3 with 64GB of storage space, and the two with the Intel Core i7, will not ship or hit retail in the U.S. and Canada until Aug. 31, more than three months from now. That's also when Microsoft will begin shipping and start selling all of the Surface Pro 3 models and accessories in 26 other markets, including the U.K., China, France, Germany and Japan.

Those schedules are similar to and different from past editions.

The original Surface Pro, for example, was finalized with pricing and specifications in late November 2012, and shipped in early February 2013, a stretch of about 10 weeks. But the second-generation Surface Pro 2, unveiled in September 2013, went on sale six weeks later.

For those who thought Microsoft jumped the gun with its rollout, Ross Rubin, principal analyst at Reticule Research, had an explanation.

"Announcing the Surface Pro 3 prior to WWDC [Worldwide Developers Conference] but also in advance of its shipping would be one way to get in front of Apple's early June announcements," Rubin wrote in an email reply to questions. "In fact, [Panos] Panay even referenced rumors that Apple was going to add support for simultaneous app viewing on the iPad."

As Rubin said, Apple's developer conference, WWDC, is just around the corner: The confab kicks off June 2, less than two weeks from today, with a keynote where company executives, including CEO Tim Cook, will almost certainly trumpet the new iOS 8 and the latest version of OS X.

Panay, the head of Microsoft's Surface team, did make a subtle reference to rumors that iOS 8 may break with tradition and include a split-screen mode for the iPad. iOS has never let two apps display simultaneously; instead, each app appears in a full-screen mode, and interaction between apps is clumsy and limited.

"There's rumors of other side-by-side computing," Panay said yesterday near the end of the Surface Pro 3 introduction. "I'm showing you side-by-side computing. This is side-by-side computing. This is Windows," Panay boasted as he demonstrated Windows 8.1's split-screen mode on the tablet. "There's no tricks, no gimmicks, no nothing. It just works."

Microsoft has long highlighted Windows' ability to show two "Modern," nee "Metro" apps in the tile-based, touch-first user interface (UI) in its anti-iPad marketing.

The Redmond, Wash. developer may also have wanted to strut the Surface Pro 3 before Apple refreshed its MacBook Air, the lightweight notebook Panay used yesterday as a foil for the new Surface. Several times Panay pulled out a MacBook Air or referenced it -- "Best in class, there's no debate," he said at one point -- to hammer home Microsoft's pitch that its new device is not as much a tablet as a notebook replacement.

Microsoft began taking pre-orders for the Surface Pro 3 Wednesday, but will not ship the first models until June 20, while the remaining configurations (including the $799 tablet) won't reach retail until late August.

Many pundits expect Apple to unveil a MacBook Air with a higher-resolution Retina screen, a change that would eliminate one of the Surface Pro 3's advantage's, its much sharper screen.

The start of pre-sales for Surface Pro 3 also knocked its predecessor, 2013's Surface Pro 2, out of Microsoft's online store. There was no easy way Wednesday to order the latter online, although Computerworld eventually found the not-that-old device after digging through a list of graduation gift suggestions.

With the Surface Pro 2 hors de combat, Microsoft is in a situation similar to Apple's of late 2012, when it introduced revamped iMac desktops, but then had none to sell for first weeks, then months as supplies dribbled out of factories in early 2013.

Microsoft is not in the same kind of pinch, said Stephen Baker, analyst with the NPD Group and a specialist in U.S. technology retail sales.

"The channel has plenty of Surface Pro 2, and no one is sending them back," Baker said today. "Three-and-a-half, four weeks after announcement isn't particularly long. What is odd is that not everything [in the Surface Pro 3 line] will be available at that point [in late June]. I don't understand why the entry level and the two premium models aren't also available then."

The Surface Pro 2 listings on Microsoft's e-store showed the same price as before the Surface Pro 3's unveiling Tuesday: $899 to $1,799.

"The Surface Pro 2 is something of a competitor to the Pro 3, and, with the exception of a bit more portability, the Pro 3 has it beat on value in just about every way," said Rubin. "So one might expect some closeout pricing on the Pro 2 and its accessories prior to the launch of the 3."

But not yet. Today, Best Buy, a key Microsoft retail partner, showed Surface Pro 2s in stock but had not discounted them.

Retail availability is also less of a concern to Microsoft than to Apple, Rubin maintained. "Surface Pro has seen a lot of its success in commercial channels," he said, referring to large distributors, like CDW and Ingram Micro, that many businesses, government agencies, schools and other organizations use to buy hardware.

The Surface Pro 3, analysts have concluded, targets the enterprise, with some spillover into early adopter ranks, the markets in which earlier Surface Pro devices have gained some traction.